A tricyclic compound amonafide 5-amino-2-2-(dimethylamino)ethyl!-1H-benzde!isoquinoline-1,3(2H)-dione! is the most famous fused polycyclic heterocycle antitumor compound having a cyclic imido moiety ##STR2## in its molecule. However, it is reported that amonafide showed a strong bone marrow toxicity and a poor efficacy in clinical tests carried out hitherto Drugs Fut., 17, 832 (1992)!. As a tetracyclic compound, there is reported azonafide 2-2'-(dimethylamino)ethyl!-1,2-dihydro-3H-dibenz(deh)-isoquinoline-1,3-d ione! obtained by converting the aminonaphthalene moiety of amonafide into anthracene to thereby enhance the antitumor activity in preclinical tests (WO9200281).
As fused tetracyclic heterocycle antitumor substances having a uracil structure wherein a nitrogen atom has been introduced into a cyclic imido moiety, there have been known 2-2-(dimethylamino)ethyl!pyrimid5,6,1-de!acridine-1,3,7-trione Farmaco, 47, 1035 (1992)! and 2,3-dihydro-2-2-(dimethylamino)ethyl!-1H,7H-naphthylidino3,2,1-ij!quinaz oline-1,3,7(2H)-trione J. Med. Chem., 37, 593 (1994)!. However each of these compounds showed only a weak antitumor activity in preclinical tests. There has been reported neither pentacyclic nor hexacyclic fused heterocycle antitumor substances of this type.
The present invention aims at providing novel compounds or novel fused pentacyclic and hexacyclic heterocycle derivatives having low toxicity and excellent antitumor activity. The present invention also aims at providing a process for producing these compounds and medicinal compositions containing as the active ingredient these compounds.